The reasons for a hard stomach are as follows: 1, due to unhygienic diet, part of the food in the stomach will produce toxins, after eating will lead to a hard stomach. 2, may be due to irregular work and rest, do not eat on time or too hungry, too full, will lead to intestinal absorption disorders, long-term so there will be a hard stomach. 3, due to eating too fast, chewing insufficiently lead to the food can not be effectively digested and decomposed. Can not get effective digestion and decomposition, the intestinal tract will cause damage. 4, due to excessive pressure, directly affecting physiological functions, so that the stomach acid secretion is too much. 5, in addition, may be suffering from duodenal ulcer and acute gastritis and other gastrointestinal diseases. It is best to go to the hospital in a timely manner and have the appropriate examination and treatment.